A frontview mirror for a motor vehicle has a mirror housing with respect to a driving direction of the vehicle, a mirror element disposed at the front surface of the housing and a supporting means provided at the front side of the mirror element for adjusting the tilting angle of the mirror element. The mirror element comprises a mirror plate (glass mirror plate) and a mirror holder for fixing the mirror plate thereto by bonding means or the like.
The mirror holders are structurally classified into two types roughly; one is a one piece type mirror holder integrally provided with a spherical pivot projecting from a front surface of a central portion of the front surface and the other is a composite type mirror holder in which a detachable holder plate separated from a mirror body of the mirror holder is preliminary molded and is engaged into an aperture provided at the central portion of body of the mirror holder, thereby both are assembled into a unit.
The composite type mirror holder has recently become popular for reason of better solving the problem of assembling a structure for adjusting a tilting angle of the mirror which problem a one type mirror holder cannot adequately solve. A composite type mirror holder is disclosed in U.S. Pat. No. 4,645,164. The mirror holder has a mirror body mounted with a mirror plate on a rear surface thereof, a holder plate engaging an aperture provided in the mirror holder, and a bolt shaped supporting means prepared as another component. The holder plate has several external lugs protruded outwardly and a periphery provided with several edges, and the mirror holder has apertures shaped so as to be opposite the holder plate, and guiding members for detachably assembling the bolt shaped supporting means to the front surface of the mirror holder. Further, the bolt shaped supporting means has a cam portion for securing the holder plate to prevent it from comming off from the aperture and a structure for determining its position.
Drawbacks of a conventional mirror holder of this type consists in that the holder plate by merely engaging the aperture formed in the holder does not have a holding force and the holder plate is easily disengaged due to a vibration or an impact during the vehicle traveling which may cause loosening of the engaged portion. Therefore, it is conventionally necessary for the mirror holder to be assembled so that the holder plate is engaged into the aperture formed in the holder and, thereafter the supporting means is mounted to the guiding means in order to hold the holder plate from disengaging therefrom. As described above, it is necessary for the conventional mirror holder that another component is used in order to secure the holder plate to the body of the mirror holder and there has been an inevitable defect that the process of assembling becomes complicated.
It is therefore an object of present invention to provide a two piece type mirror holder for a rearview mirror which has a sufficient holding strength for a mirror plate.
It is another object of present invention to provide a two piece type mirror holder for a rearview mirror which can precisely engage the mirror plate and can be readily associated without another component separated therefrom.
It is still another object of present invention to provide a holding device of a mirror element for a rearview mirror comprising a two piece type mirror holder.